using System;

public class Hello
{
    static void Main()
    {
        var d = int.Parse(Console.ReadLine().Trim());
        if (d <= 3) Console.WriteLine(0);
        else getAns(d);
    }
    static void getAns(int d)
    {
        var a = d / 4;
        var b = (d - 2 * a) / 2;
        Console.WriteLine(a * b);
    }
}